Clostridium tetani

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Clostridium tetani
Clostridium tetani forming spores
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Bacillota
Class: Clostridia
Order: Eubacteriales
Family: Lachnospiraceae
Genus: Clostridium
Species:
C. tetani
Binomial name
Clostridium tetani
Flügge, 1881

Clostridium tetani is a common soil bacterium and the causative agent of

tetanus toxoid
vaccines, which are often administered to children worldwide.

Characteristics

A diagram of C. tetani showing the bacterium alone, with a spore being produced, and the spore alone

Clostridium tetani is a

Gram-positive bacterium, typically up to 0.5 μm wide and 2.5 μm long.[1] It is motile by way of various flagellums that surround its body.[1] C. tetani cannot grow in the presence of oxygen.[1] It grows best at temperatures ranging from 33 to 37 °C.[1]

Upon exposure to various conditions, C. tetani can shed its flagellums and form a

antiseptics, and boiling for several minutes.[2] The spores are long-lived and are distributed worldwide in soils as well as in the intestines of various livestock and companion animals.[3]

Evolution

Clostridium tetani is classified within the genus Clostridium, a broad group of over 150 species of Gram-positive bacteria.

C. difficile, which is more closely related to members of genus Peptostreptococcus than to C. tetani.[4]

Role in disease

A man suffering muscle spasms from tetanus, painted by Charles Bell in 1809

While C. tetani is frequently benign in the soil or in the intestinal tracts of animals, it can sometimes cause the severe disease

gamma-aminobutyric acid at motor nerve endings.[5] This blockade leads to the widespread activation of motor neurons and spasming of muscles throughout the body.[6] These muscle spasms generally begin at the top of the body and move down, beginning about 8 days after infection with lockjaw, followed by spasms of the abdominal muscles and the limbs.[5][6] Muscle spasms continue for several weeks.[6]

The gene encoding tetanospasmin is found on a plasmid carried by many strains of C. tetani; strains of bacteria lacking the plasmid are unable to produce toxin.[1][5] The function of tetanospasmin in bacterial physiology is unknown.[1]

Treatment and prevention

Clostridium tetani is susceptible to a number of

tetanus immune globulin to bind up circulating tetanospasmin.[6] Additionally, benzodiazepines or muscle relaxants may be given to reduce the effects of the muscle spasms.[1]

Damage from C. tetani infection is generally prevented by administration of a

DTaP.[6] This is given in several doses spaced out over months or years to elicit an immune response that protects the host from the effects of the toxin.[6]

Research

Clostridium tetani can be grown on various anaerobic

blood agar.[1] Cultures grow particularly well on media at a neutral to alkaline pH, supplemented with reducing agents.[1] The genome of a C. tetani strain has been sequenced, containing 2.80 million base pairs with 2,373 protein coding genes.[7]

History

Clinical descriptions of tetanus associated with wounds are found at least as far back as the 4th century

prophylaxis and treatment.[6] In World War I, injection of tetanus antiserum from horses was widely used as a prophylaxis against tetanus in wounded soldiers, leading to a dramatic decrease in tetanus cases over the course of the war.[9] The modern method of inactivating tetanus toxin with formaldehyde was developed by Gaston Ramon in the 1920s; this led to the development of the tetanus toxoid vaccine by P. Descombey in 1924, which was widely used to prevent tetanus induced by battle wounds during World War II.[6]

References

  1. ^
    ISBN 9781455700905
    .
  2. ^
    ISBN 978-1-259-85980-9
    .
  3. ^
    ISBN 9781118960608
    .
  4. ISBN 9780125950206
    .
  5. ^ a b c d Todar K (2005). "Pathogenic Clostridia, including Botulism and Tetanus". Todar's Online Textbook of Bacteriology. p. 3. Retrieved 24 June 2018.
  6. ^ a b c d e f g h i j k l Hamborsky J, Kroger A, Wolfe C, eds. (2015). "Chapter 21: Tetanus". The Pink Book - Epidemiology and Prevention of Vaccine-Preventable Diseases (13 ed.). U.S. Centers for Disease Control and Prevention. pp. 341–352. Retrieved 24 June 2018.
  7. PMID 12552129
    .
  8. PMID 8609513
    .
  9. S2CID 30610331
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Clostridium_tetani&oldid=1180790893"